Continuously casting pipe



Sept. 13, 1938. M. TAMA CONTINUOUSLY CASTING PIPES Filed June 30, 1937Zzvenlonflfamve/ 7677M.

Zz/J/M w @444? 7%QJJM Patented Sept. 13, 1938 UNITED STATES,

2,130,202- CONTINUOUSLY oss'rmo PIPE Manuel Tama, Zurich, SwitzerlandApplication June 30, 1937, Serial No. 151,241 In Germany August 18, 1936Claims.

The present invention relates to a method and an apparatus forcontinuously casting pipes or tubes adapted to be further treated byrolling, drawing and the like. The new method may be 5 utilized forcasting tubes or pipes from all suitable metals used in the industry, assteel, copper, brass, aluminium, etc. It is further adapted to producepipes or tubes having walls of such thicknesses as to be able to befurther treated according to usual methods, that is to say, tubes orpipes are intended to be produced having wall thicknesses of about 4-10mm. and a diameter of about 40-200 mm.

Under the expression continuously casting the production of tubes orpipes in infinite length is to be understood. By connecting a cuttingdevice to the casting apparatus it is, however, possible to producetubes or pipes of suitable length for the further manufacture.

Various methods have already been proposed to produce castings of solidcross section and some of these methods have been successful inpractice. For the production of hollow castings, however, no methods areknown hitherto which have been successful in practice.

The method according to the present invention consists in this, that themetal is poured from above into a mold which, in a well known manner,may be reciprocated in the direction of its 20 longitudinal axis, andthat the solidified tube or pipe is drawn off from the mold by means ofa conveying device, the solidification heat being substantiallyconducted away from the interior to the exterior.

3' The new method is further characterized by using an artificiallycooled mold and a mandrel of ceramic material as exterior and interiormold respectively. The liquid hot metal is preferably supplied in thedirection from the axis to the exterior circumference of the tube orpipe to be formed.

The apparatus forming the subject matter of the invention substantiallyconsists of a hollow tube serving to pour in the liquid metal, the lowerend of said tube being closed .by a bottom and provided with lateraloutlet openings. The pouring in tube advantageously simultaneouslyserves to carry the ceramic mandrel which 59 preferably consists ofgraphite.

One embodiment of an apparatus for carrying out the method according tothe invention is shown by way of example in the accompanying drawing.

5 In this drawing:

Fig. 1 is an elevation of a casting apparatus partly in section,

Fig. 2 is a side elevation of the apparatus shown in Fig. 1 and Fig. 3is a detail sectional view showing on a 5 larger scale the upper end ofthe mold.

' The operation of the method and the apparatus may first of all beexplained by the aid of Figures 1 and 2.

The liquid metal contained in a ladle l is m poured into an intermediatereceptacle 2, consisting of refractory material. The intermediatereceptacle 2 is provided with a partition wall 3 provided at the lowerend with an opening 4, so that the two compartments 5 and 6 of the re-15 ceptacle 2 communicate with each other. The metal supplied to thecompartment 5 directly flows into the compartment 6. As, however, thetwo compartments 5 and 6 communicate with each other at the bottom only,the slags floating 20 on the upper surface of the metal in thecompartment 5 of the receptacle 2 cannot reach the compartment 6. Themetal from the compartment 6 flows through a pipe 1 consisting of suit-'able material and provided at the lower end with 5 outlets 8 openinginto the mold 9 which is surrounded by a space l0 cooled by water oranother liquid.

The cooling water is supplied through a socket II and withdrawn througha pipe ii. The water-cooled mold 9 together with the water space I0, thesocket H and pipe i2, are, in a well known manner, reciprocated in thelongitudinal direction of the pipe to be produced, and thisreciprocation may, for instance, be efiected by an eccentric means l3,l4 driven by means of a pulley IS.

The metal flowing through the pipe I fills the space between theexterior wall of the mold 9 and the interior mandrel l6. In this manner,a 4( tube or pipe I! is produced which slowly is withdrawn from below byrolls l8.

The rolls l8 are driven by means of a worm l9, fixed upon the shaft ofthe pulley i5 and engaging a worm wheel 20 connected to one of the rollsH3.

The mandrel l6 consists of ceramic material and is intentionally notmade of metal to prevent heat from being conducted away from theinterior. An essential point in carrying out the new method is thewithdrawal of heat to the exterior by the contact of the liquid metalwith the cooled walls of the mold 9. As known from experience, thepoured in material very quickly shrinks at the point of contact with thewall of the mold 9, so that a hollow space is formed between the pipe ortube l1 and the wall of the mold 9 which hollow space is the greater,the more the tube produced progresses downwardly. In spite of the fact,that after shrinkage no contact exists any more with the wall of themold, heat is disbursed by radiation to the exterior.

As the mandrel l6 consists of a ceramic material and is not cooled, buton, the contrary is continuously maintained upon higher temperatures bythe flowing in metal, practically no heat is conducted away from theinterior of the pipe or tube l1. Moreover, in this manner the portionsof the tube ll facing the q centre slower solidify than the exteriorportions. The metal, therefore, more slowly shrinks at the interiorportions than at the exterior portions and sticking of the tube or pipeI! to the mandrel I6 is already prevented by this essential measure, 1.e. by conducting away heat to the exterior only.

A further measure for preventing sticking of the tube or pipe I] to themandrel I6 is the manufacture of the mandrel of graphite, a materialupon which, as is well known, most metals have no moistening effect.

Finally it is of great importance to use a mandrel i6 which is taperedin such a manner, that its diameter decreases towards the lower end.

Fig. 3 shows on a larger scale further details of the most importantportions of the casting mold and the mandrel, i. e. the part of theapparatus, at which the tube or pipe is formed.

Here again the molten metal is introduced into the casting mold by meansof the tube 1 consisting of a material resisting the attack of the metalpoured into it. Such materials are known either as ceramic or asmetallic materials. The heating of the tube 1 to the temperature of themetal flowing through may, in a well known manner be effected, forinstance by means of electric resistances so as to preventsolidification of the metal between the walls. The lower end of the pipeI is provided with a bottom 2| and with a plurality of openings 8,through which the metal may flow out. These outlets preferably extend tothe bottom 2|, so that no bags whatever are formed, which would preventthe free flow of the metal. Welded to the bottom 2| is a bolt 22 servingto connect the mandrel l6 consisting of a ceramic material. The mandrelI6 is held by means of a washer 23 and a pin 24. In this figure, 9 isthe wall of the casting mold which, in a well known manner, is made ofcopper and surrounded by a water space iii to obtain a violent coolingeffect.

The movement of the casting mold 9 in the direction of the longitudinalaxis of the tube 1 may be chosen as desired provided this movementallows the formation of the tube or pipe l1.

Preferably, this movement is so chosen that 11., downward movement ofthe casting mold 9 cor responds to the feed of the tube or pipe II,whereas the upward movement is relatively fast, as is -mold, a mandrelarranged in said mold in spaced relation to the inner periphery thereof,a tube to support said mandrel and to supply melted metal to be cast,said tube being spaced from the inner periphery of said mold a distancegreater than said mandrel to provide an annular space above said mandrelof greater cross section than that of the tube to be cast.

2. In a device for continuously casting metal tubes, the combinationcomprising, a water cooled mold, a mandrel arranged in said mold inspaced relation to the inner periphery thereof, said mandrel beingcomposed of a refractory substance and having its greatest diameter atthe top thereof, a. tube of less diameter than the mandrel to supportsaid mandrel and to supply metal to be cast, and said tube being closedat its lower end and having openings directly above the closure.

3. In a device for continuously casting metal tubes, the combinationcomprising, a water cooled mold, a mandrel arranged in said mold inspaced relation to the inner periphery thereof, a tube of smallerdiameter than said mandrel arranged coaxially of said mold, a plateclosing the lower end of said tube, a bolt depending from said plate tosupport said mandrel, and openings in said tube above said plate.

4. In a device for continuously casting metal tubes, the combinationcomprising, a mold, means rapidly to conduct heat away from said mold, amandrel supported in said mold in spaced relation to the inner peripherythereof, said mandrel being of a substance of low heat conductivity sothat the exterior surface of a cast tube will cool faster than theinterior surface thereof, said mandrel having its greatest diameter atthe top, means to introduce melted metal to be cast into said mold abovesaid mandrel, and means to remove a cast tube from said mold below saidmandrel.

5. The method of casting continuous lengths of seamless metal tubeswhich comprises, continu-- ously feeding molten metal into an annularmold between a sleeve and a mandrel, causing said cast tube to cool onits exterior surface and shrink away from said sleeve, later causingsaid cast tube to cool on its interior surface and shrink away from saidmandrel, and finally withdrawing the solidified tube from beneath saidmold.

MANUEL TAMA.

